Examples of com.sleepycat.je.dbi.SortedLSNTreeWalker

com.sleepycat.je.dbi.SortedLSNTreeWalker
SortedLSNTreeWalker uses ordered disk access rather than random access to iterate over a database tree. Faulting in data records by on-disk order can provide much improved performance over faulting in by key order, since the latter may require random access. SortedLSN walking does not obey cursor and locking constraints, and therefore can only be guaranteed consistent for a quiescent tree which is not being modified by user or daemon threads. The class walks over the tree using sorted LSN fetching for parts of the tree that are not in memory. It returns LSNs for each node in the tree, except the root IN, in an arbitrary order (i.e. not key order). The caller is responsible for getting the root IN's LSN explicitly.
A callback function specified in the constructor is executed for each LSN found.
The walker works in two phases. The first phase is to gather and return all the resident INs using the roots that were specified when the SLTW was constructed. For each child of each root, if the child is resident it is passed to the callback method (processLSN). If the child was not in memory, it is added to a list of LSNs to read. When all of the in-memory INs have been passed to the callback for all LSNs collected, phase 1 is complete.
In phase 2, for each of the sorted LSNs, the target is fetched, the type determined, and the LSN and type passed to the callback method for processing. LSNs of the children of those nodes are retrieved and the process repeated until there are no more nodes to be fetched for this database's tree. LSNs are accumlated in batches in this phase so that memory consumption is not excessive. For instance, if batches were not used then the LSNs of all of the BINs would need to be held in memory.

        GatherLSNs gatherLsns = new GatherLSNs();
        long rootLsn = dbImpl.getTree().getRootLsn();
        List<DatabaseException> savedExceptions =
            new ArrayList<DatabaseException>();


        SortedLSNTreeWalker walker =
            new SortedLSNTreeWalker(new DatabaseImpl[] { dbImpl },
                                    false /*setDbState*/,
                                    new long[] { rootLsn },
                                    gatherLsns, savedExceptions, null);
        walker.walk();


        /* Print out any exceptions seen during the walk. */
        if (savedExceptions.size() > 0) {
            out.println(savedExceptions.size() +
                        " problems seen during tree walk for checkLsns");

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        DatabaseImpl dbImpl = DbInternal.dbGetDatabaseImpl(db);
    
        /* Get all the lsns in the database. */
        GatherLSNs gatherLsns = new GatherLSNs();
        long rootLsn = dbImpl.getTree().getRootLsn();
        SortedLSNTreeWalker walker = 
            new SortedLSNTreeWalker(dbImpl,
                                    false, // don't remove from INList
                                    false, // don't set db state
                                    rootLsn,
                                    gatherLsns);
        walker.walk();
        Set lsnsInTree = gatherLsns.getLsns();
        lsnsInTree.add(new Long(rootLsn));
    
        /* Get all the files used by this database. */
        Iterator iter = lsnsInTree.iterator();

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        GatherLSNs gatherLsns = new GatherLSNs();
        long rootLsn = dbImpl.getTree().getRootLsn();
        List<DatabaseException> savedExceptions =
            new ArrayList<DatabaseException>();


        SortedLSNTreeWalker walker =
            new SortedLSNTreeWalker(dbImpl,
                                    false, // don't set db state
                                    rootLsn,
                                    gatherLsns,
                                    savedExceptions,
                                    null);
        walker.walk();


        /* Print out any exceptions seen during the walk. */
        if (savedExceptions.size() > 0) {
            out.println(savedExceptions.size() +
                        " problems seen during tree walk for checkLsns");

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Related Classes of com.sleepycat.je.dbi.SortedLSNTreeWalker

com.sleepycat.je.cleaner.OffsetList

com.sleepycat.je.cleaner.VerifyUtils

com.sleepycat.je.log.entry.LNLogEntry

com.sleepycat.je.log.entry.LogEntry

com.sleepycat.je.tree.BINDelta

com.sleepycat.je.tree.ChildReference

com.sleepycat.je.tree.DIN

com.sleepycat.je.tree.DupCountLN

com.sleepycat.je.tree.IN

com.sleepycat.je.tree.LN

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